LayerSurfaceV1 exposes "mapped" property which does not exist

[heuer]

See https://github.com/flacjacket/pywlroots/blob/main/wlroots/wlr_types/layer_shell_v1.py#L128

and

https://wayland.emersion.fr/wlroots/wlr/types/wlr_layer_shell_v1.h.html#struct-wlr_layer_surface_v1

The underlying wlr_surface exposes mapped, though.

Solution: Remove the property.